Carbon fiber undergoes high-temperature carbonization (above 1000℃) in an inert gas environment during manufacturing. This process involves the release of non-carbon elements (such as oxygen and nitrogen) and the rearrangement of carbon atoms, resulting in a disordered graphite structure. The surface becomes relatively smooth, lacking active functional groups, thus exhibiting inertness and low reactivity. As a reinforcing fiber in composite materials, the poor adhesion between carbon fiber and the polymer, along with weak interfacial bonding, leads to low interlaminar shear strength in fiber-reinforced polymer matrix composites, affecting their applications. Improving the fiber surface or the interfacial properties between carbon fiber and the polymer is crucial for obtaining high-performance carbon fiber-reinforced polymer matrix composites.
Carbon fibers typically undergo surface treatment (such as anodizing) and sizing before leaving the factory. Some researchers further treat the carbon fiber surface to increase its surface roughness and polar groups, thereby improving its affinity with the polymer. Currently, methods for surface modification of carbon fibers mainly include oxidation treatment, surface coating treatment, plasma treatment, surface grafting treatment, gamma-ray treatment, and ultrasonic treatment.
